The invention is based on a pump unit as defined hereinafter.
One such pump unit is already known (DE 42 39 361 A1), in which a body press-fitted into an outflow bore is provided with axially parallel openings that discharge into a seat valve. This valve has a disk-shaped rubber plate, which is received on the body and cooperates with a valve seat formed on the body. The seat valve is intended to open toward the ambient air and be permeable to leaking brake fluid but to prevent the entry of splashing water into the outflow bore.
The body that has the seat valve indeed comprises only two components and is simple to mount. Nevertheless, the valve is not failsafe, since a foreign body can impair its closing function. Moreover, the valve seems to be disproportionately large, since under normal wear conditions leaking brake fluid does not occur in great quantities in the pump unit.